An exhaust gas recirculation (EGR: Exhaust Gas Recirculation) device is known, which causes a part of exhaust gas to recirculate into an intake passage, in order to prevent knocking and to achieve effects such as improvement in fuel economy due to reduction in pumping loss. Furthermore, JP2012-7547A discloses a low-pressure loop EGR device as an EGR device applied to internal combustion engines with turbo superchargers, which device causes a part of exhaust gas (hereinafter, also referred to as EGR gas) to recirculate into the intake passage at a part upstream of a compressor of the turbo supercharger.
This low-pressure loop EGR device includes a differential pressure generating valve for ensuring a differential pressure between the intake passage and an exhaust passage even in operating regions with low intake amounts. Furthermore, in the operating regions with low intake amounts, opening and closing of the EGR valve to adjust the amount of EGR gas is controlled in a state in which the differential pressure generating valve is controlled to a closing side. That is to say, the differential pressure is generated at the differential pressure generating valve, and the amount of EGR gas is adjusted by the EGR valve. Moreover, in the above document, an operated order of the differential pressure generating valve and the EGR valve are determined for the controlling, in a case in which the EGR ratio is to be changed equal to or more than a predetermined changing amount.